A three-dimensional electronic, biological, chemical, thermal management, or electromechanical apparatus and method thereof. One or more layers of a three-dimensional structure are deposited on a substrate. The three-dimensional structure is configured to include one or more internal cavities using, an extrusion-based additive manufacturing system enhanced with a range of secondary embedding processes. The three-dimensional structure includes one or more structural integrated metal objects spanning the one or more of the internal cavities of the three-dimensional structure for enhanced electromagnetic properties and bonded between two or more other metal objects located at the same layer or different layers of the three-dimensional structure.